• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.877-884
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• 2010

This paper presents a fast IP mobility management scheme in vehicular networks where multiple wireless network interfaces are used to perform the fast handover without packet loss and handover latency. In order to do that, the IETF standard HMIPv6 has been extended, where multiple simultaneous tunnels between the HMIPv6 MAP and the mobile gateway are dynamically constructed. The architecture for supporting multiple tunnels has been designed and both mathematical analysis and simulation using NS-2 have been done for performance evaluation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.69-77
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• 2010

This paper presents a fast IP mobility management scheme in heterogeneous networks using the multiple wireless network interlaces. More specifically, in order to minimize the packet loss and handover latency due to handover, the E-HMIPv6, IETF HMIPv6 has been extended, is presented where the multiple tunnels between E-MAP and mobile node are dynamically constructed. E-HMIPv6 is composed of the extension of IETF HMIPv6 MAP, handover procedure, and simultaneous multiple tunnels. In order to demonstrate superior to the proposed method, the NS-2 simulation has done for performance evaluation of TCP and UDP-based application comparison with the existing mobility management method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1412-1418
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• 2005

Recently, more and more portable terminals probably have multiple interfaces to be connected to different access technologies. Each technology has its specific characteristics in terms of coverage area, bandwidth, reliability, etc. For example, the mobile node is equipped with three heterogeneous interfaces; IEEE 802.1lb MLAM link, CDMA Cellular link, and 802.16 WiMAX link These mobile nodes may be reachable through different links at the same time or use each interface alternately depending on the network environment. As like this, the portable terminal equipped multiple interfaces can have many benefits; it should be connect to Internet through other interface in case of occurring to failure for currently activate interface, and it should share a mount of traffic efficiently per interface etc. This environment is called end node Multihoming. However, current most Internet protocols are designed originally with single interface in mind. So these potocols do not provide methods for supporting simultaneous diffentiated use of multiple access technologies. In this paper, firstly we have to refer technical consideration items to use multiple interfaces based on IPv6 simultaneously. And we should propose extended registration mechanism for multiple addresses being acquired from interfaces to support reliable accessibility and vertical handover.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.338-343
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• 2007

WCDMA, WLAN, WiBro등과 같은 다양한 이기종 무선 네트워크들이 증가하면서 중첩된 네트워크가 발생하게 되어, 이기종망간의 vertical handover가 증가하게 되고 효율적인 Network 자원관리 필요성이 증가하였다. 이를 위해 특화된 CRRM을 활용한 중첩된 network들의 통합 자원 관리방안을 제안한다. 제안된 방안은 bandwidth와 사용자의 수를 고려하여 bandwidth를 adaptation 시키거나 forced vertical handover를 진행하여 자원을 관리하며, user는 별도의 handover discover 단계를 생략하고 vertical handover를 진행할 수 있으며, Multiple interface를 사용하여 MCoA를 등록하고 다양한 무선네트워크를 이용하여 데이터 전송이 가능해진다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3A
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• pp.217-224
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• 2010

In this paper, we propose a hard handover algorithm for a base station's self-optimization, one of the automatic operational technologies for the 3GPP LTE systems. The proposed algorithm simultaneously considers a mixed target sell selection method for optimal selection and a multiple parameter based active hysteresis method with the received signal strength from adjacent cells and the cell load information of the candidate target cells from information exchanges between eNBs through X2 interface. The active hysteresis method chooses optimal handover hysteresis value considering the costs of the various environmental parameters effect to handover performance. The algorithm works on the optimal target cell and the hysteresis value selections for a base station's automatic operational optimization of the LTE system with the gathered informaton effects to the handover performance. The simulation results show distinguished handover performances in terms of the most important performance indexes of handover, handover failure rate and load balancing.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.79-87
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• 2010

This paper proposes a L3 handover method to minimize packet loss for supporting service continuity to IMS Terminal which has a single WLAN interface. The existing IMS based handover solution is able to support handover between different access networks in case that a terminal has multiple interfaces. That is, WLAN terminals need multiple interfaces to connect with one or more access networks. This proposed method configures IP address for the terminal in target WLAN previously by using Candidate Access Router Discovery(CARD) mechanism. Also, in the proposed method, service continuity server performs L3 connection establishment in target WLAN and registration to IMS server instead of the terminal. And then session control mechanism based on SIP is performed to support service continuity. We analyzed handover latency and signaling cost in the proposed method and existing method to show the improved performance by the proposed method.

• Journal of KIISE:Information Networking
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• v.36 no.3
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• pp.163-172
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• 2009

Various terminals equipped with multiple interfaces may receive services from wireless networks when they pass through the overlaid heterogeneous networks, and thus the vertical handovers across the wireless networks increases, which will become a big problem in the network resource management. This problem can be efficiently solved by common radio resource management (CRRM). In this paper, we propose two operation algorithms based on network selection jointly with vertical handover as the key CRRM strategies. When a new user tries to get services, the CRRM can choose the best target network according to the proposed Integrated Network Selection Algorithm. When the network cannot satisfy the request from the new users, the proposed Integrated Vertical Handover Algorithm moves existing users to neighborhood networks to accommodate new users. The performance of the proposed algorithms has been validated through extensive simulations.

• ETRI Journal
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• v.19 no.3
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• pp.141-168
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• 1997

The base station (BS) in the CDMA Mobile System (CMS) connects calls through the radio interface and is designed to provide mobile subscribers with high quality service in spite of mobile subscribers motions. The BS consists of multiple base station transceiver subsystems (BTSs), a base station controller (BSC) and a base station manager (BSM). This paper is concerned with the BSC and the BSM. The BSC is located between the BTSs and the mobile switching center (MSC) connected with the public network, and to mobile subscribers via the BTSs. The BSM provides operator-interfaces per the BS and takes responsibility of operation and maintenance (OAM) of the BS. Design of the BSC is based on two module types: functional module and unit module. The functional module is used to support new services easily and the unit module to increase the system capacity economically. Both modular types are easily achieved by inserting the corresponding modules to the system. Particularly, in order to efficiently support the soft handover which is one of CDMA superior advantages, the BSC adopts a large high-speed Packet switch connecting up to 512 BTSs, and thus mobile subscribers can be provided with soft handover in high probability. The BSM is based on a commercial workstation to support OAM functions efficiently and guarantee high reliability of the functions. The BSM uses graphical user interface (GUI) for efficient OAM functions of the BS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.677-686
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• 2010

In this paper, we propose the virtual interface management scheme on the multi-mode mobile node for supporting multiple connections to various access networks in fixed mobile convergence (FMC) networks. The proposed scheme supports the virtualization of multiple physical network interfaces by presenting only the virtual interface to beyond IP layers and hiding physical network interfaces from them. In the proposed scheme, only one IP address is allocated to virtual interface without any IP allocations to physical network interfaces. Therefore, the proposed scheme does not change its IP address and keep it during the vertical handover, so that it can support the seamless handover of real-time multimedia services among heterogeneous access networks. The proposed scheme is implemented on the multi-mode mobile node with multiple network interfaces by using NDIS (Network Driver Interface Specifications) libraries. Through the mobility test-bed and the test application of virtual interface, we evaluate and analyze the performance of the proposed scheme.

• Journal of Information Processing Systems
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• v.8 no.4
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• pp.603-620
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• 2012

Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require Mobile Nodes (MNs) to be involved in the mobility support signaling. In the case when multiple interfaces are active in an MN simultaneously, each data flow can be dynamically allocated to and redirected between different access networks to adapt to the dynamically changing network status and to balance the workload. Such a flow redistribution control is called "flow mobility". In the existing PMIPv6-based flow mobility support, although the MN's logical interface can solve the well-known problems of flow mobility in a heterogeneous network, some missing procedures, such as an MN-derived flow handover, make PMIPv6-based flow mobility incomplete. In this paper, an enhanced flow mobility support is proposed for actualizing the flow mobility support in PMIPv6. The proposed scheme is also based on the MN's logical interface, which hides the physical interfaces from the network layer and above. As new functional modules, the flow interface manager is placed at the MN's logical interface and the flow binding manager in the Local Mobility Anchor (LMA) is paired with the MN's flow interface manager. They manage the flow bindings, and select the proper access technology to send packets. In this paper, we provide the complete flow mobility procedures which begin with the following three different triggering cases: the MN's new connection/disconnection, the LMA's decision, and the MN's request. Simulation using the ns-3 network simulator is performed to verify the proposed procedures and we show the network throughput variation caused by the network offload using the proposed procedures.